/* =============================================================================
 * ui_template_item_picker.ts
 * 항목 고르기 모달 — 구조물집계표 항목(SS 한 줄)을 마스터 · 회사 · 개인 세 그룹 나무에서 고름.
 * 키(SS · UA …)는 앞에 내세우지 않고 이름으로 보임 · 키는 마우스를 올리면(PLAN.md 21-0).
 *
 *   const result = await openItemPicker({ current, canCopy, projectId, structureId });
 *   result.action = "apply"(result.item = 21-1 `summary_item`) | "clear" | "cancel"
 *
 * 26-3b — 카드 · 편집 · [재적용] · [개인에 저장] 은 **고르는 구조물의 복사본**(`structureId`) 기준.
 * 나무 개인 그룹 · 폴더를 오른쪽 클릭하면 「새 항목」(프로젝트에서 새 항목 → 개인 층에도 만들고 폼에 지정).
 * ========================================================================== */

import "./ui_template_item_picker.css";
import { API_BASE_URL } from "@config/config_frontend";
import { createButton, createInputField, el, showToast } from "./ui_template_elements";
import {
  buildTree,
  filterRows,
  isCurrent,
  layerOf,
  ownerOf,
  pathIds,
  rowId,
  toSummary,
  type PickNode,
  type PickerLayer,
  type PickerRow,
  type SummaryItem,
  type TreeLabels,
} from "./ui_template_item_picker_data";
import { t } from "./ui_template_locale";
import { openModal } from "./ui_template_modal";
import { createTreeRow, renderTree, type TreeMenuItem, type TreeNode } from "./ui_template_tree";
import { askFields } from "./ui_template_item_picker_ask";
import { projectItems, type CreatedItem } from "./ui_template_item_picker_project";
import { createItemDetail, type EditRequest } from "./ui_template_item_picker_detail";
import { createEditView, type EditView } from "./ui_template_item_picker_edit";

export type { SummaryItem } from "./ui_template_item_picker_data";

export interface ItemPickerOptions {
  /** 지금 지정된 항목 — 없으면 null */
  current: SummaryItem | null;
  /** [개인용으로 복사]를 쓸 수 있나 — 개인 층에 쓸 수 있을 때(회사 등록 뒤) */
  canCopy: boolean;
  /** 프로젝트 안에서 부르면 그 id — 카드 [수정] 이 프로젝트 복사본을 고침(없으면 원본 보기만 · 25-2d) */
  projectId?: string | null;
  /** 고르는 구조물의 id(`structure_id` · 관 지점 `pipe@측점`) — 복사본이 이 구조물 것 · 없으면(추가 전) 원본 보기만 */
  structureId?: string | null;
}

export type ItemPickerResult =
  { action: "apply"; item: SummaryItem } | { action: "clear" } | { action: "cancel" };

/** 관리 화면 진입 해시(PLAN 27-1d) — 구조물 조합 · 개인 뿌리가 열린 채 */
const MANAGE_HASH = `#/m02-master-template?${new URLSearchParams({ open: "구조물조합", root: "personal" })}`;

const labels = (): TreeLabels => ({
  layers: {
    system: t("M02_PickerSystem"),
    company: t("M02_PickerCompany"),
    personal: t("M02_PickerPersonal"),
  },
  unclassified: t("M02_PickerNoClass"),
});

/** 서버가 막은 까닭 그대로 */
function reasonOf(body: unknown, status: number): string {
  const detail = (body as { detail?: unknown } | null)?.detail;
  return typeof detail === "string" && detail ? detail : `HTTP ${status}`;
}

/** `GET /api/m02/items?all=1` = `[{layer, owner, items}]` — 줄마다 `layer` · `owner` 를 붙여 하나로 폄 */
async function loadRows(): Promise<PickerRow[]> {
  const response = await fetch(`${API_BASE_URL}/m02/items?all=1`, { credentials: "include" });
  const body = (await response.json().catch(() => null)) as
    | { layer: PickerLayer; owner: string | null; items: PickerRow[] }[]
    | { detail?: unknown }
    | null;
  if (!response.ok || !Array.isArray(body)) throw new Error(reasonOf(body, response.status));
  return body.flatMap((group) =>
    group.items.map((item) => ({ ...item, layer: group.layer, owner: group.owner })),
  );
}

/** 개인용으로 복사 — 새로 생긴 줄의 키를 돌려줌(서버가 안 주면 null) */
async function copyToPersonal(row: PickerRow): Promise<string | null> {
  const response = await fetch(`${API_BASE_URL}/m02/layers/personal/items/copy`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ from_layer: layerOf(row), from_owner: ownerOf(row), key: row.key }),
  });
  const body = (await response.json().catch(() => null)) as { key?: string } | null;
  if (!response.ok) throw new Error(reasonOf(body, response.status));
  return body?.key ?? null;
}

const NEW_TEXT = {
  menu: "새 항목",
  title: "새 항목",
  note: "{value} 안에 새 항목을 만듦 — 개인 층에도 저장되고 이 구조물에 지정됨",
  name: "이름",
  unit: "단위",
  ok: "만들기",
  cancel: "취소",
  empty: "{label} 을(를) 넣을 것",
  made: "새 항목을 만들어 지정했음 — 구조물 [저장]을 눌러야 이 구조물 복사본이 남음",
  failed: "새 항목을 만들지 못함 — {value}",
  noStructure: "구조물을 먼저 추가해야 새 항목을 이 구조물에 지정할 수 있음",
  saveLine: "[적용] 뒤 구조물 [저장]을 눌러야 이 구조물 복사본이 남음",
};

const fill = (text: string, value: string): string => text.replace("{value}", value);

const message = (error: unknown): string =>
  error instanceof Error ? error.message : String(error);

export function openItemPicker(opts: ItemPickerOptions): Promise<ItemPickerResult> {
  return new Promise((resolve) => {
    let rows: PickerRow[] = [];
    let chosen: PickerRow | null = null;
    /** 접었다 펼친 것을 다시 그려도 남기려고 펼친 줄 id 를 기억 */
    const opened = new Set<string>();
    const leafButtons = new Map<string, HTMLElement>();

    const search = createInputField({ placeholder: t("M02_PickerSearch"), compact: true });
    const treeHost = el("div", { className: "ui-item-picker__tree" });
    const detailView = createItemDetail({
      projectId: opts.projectId ?? null,
      layerLabels: labels().layers,
      hint: t("M02_PickerHint"),
      unit: t("M02_PickerUnit"),
      structureId: opts.structureId ?? null,
      onEdit: (request) => openEdit(request),
      // 개인에 저장 — 나무를 다시 받고 새 항목을 고름(개인 그룹에 뜸)
      onCreated: (created) => void load(created.key),
    });
    const cols = el("div", {
      className: "ui-item-picker__cols",
      children: [
        el("div", { className: "ui-item-picker__left", children: [search.root, treeHost] }),
        detailView.root,
      ],
    });
    const editHost = el("div", { className: "ui-item-picker__edit-host", attrs: { hidden: "" } });
    let editView: EditView | null = null;
    const applyButton = createButton({ label: t("M02_PickerApply"), variant: "filled" });
    const clearButton = createButton({ label: t("M02_PickerClear"), variant: "ghost" });
    const copyButton = createButton({ label: t("M02_PickerCopy"), variant: "ghost" });
    const manageButton = createButton({ label: t("M02_PickerManage"), variant: "ghost" });
    let close = (): void => {};

    const finish = (result: ItemPickerResult): void => {
      resolve(result);
      close();
    };

    const hint = (text: string): HTMLElement =>
      el("p", { className: "ui-item-picker__hint", text });

    const paintDetail = (): void => {
      detailView.show(chosen);
      const layer = chosen ? layerOf(chosen) : null;
      applyButton.disabled = !chosen;
      clearButton.disabled = !opts.current;
      copyButton.hidden = !(chosen && layer !== "personal" && opts.canCopy);
      manageButton.hidden = !(chosen && layer === "personal");
    };

    const choose = (row: PickerRow): void => {
      chosen = row;
      for (const [id, button] of leafButtons)
        button.classList.toggle("is-active", id === rowId(row));
      paintDetail();
    };

    /** 오른쪽 클릭 — 개인 그룹 · 폴더만 「새 항목」(경로 = 누른 폴더) */
    const menuOf = (node: PickNode): (() => TreeMenuItem[]) | undefined => {
      const folder = node.folder;
      if (!folder || folder.layer !== "personal" || !opts.projectId) return undefined;
      return () => [
        {
          label: NEW_TEXT.menu,
          run: () => void createNew(folder.path),
          disabledReason: opts.structureId ? undefined : NEW_TEXT.noStructure,
        },
      ];
    };

    const toTree = (node: PickNode, searching: boolean): TreeNode => ({
      id: node.id,
      label: node.label,
      count: node.count,
      tip: node.tip,
      menu: menuOf(node),
      open: searching || opened.has(node.id),
      run: node.row ? () => choose(node.row as PickerRow) : undefined,
      children: node.children?.map((child) => toTree(child, searching)),
    });

    const paintTree = (): void => {
      leafButtons.clear();
      const text = search.input.value;
      const searching = text.trim() !== "";
      const groups = buildTree(filterRows(rows, text), labels())
        // 찾는 중에는 결과가 없는 그룹을 감춤
        .filter((group) => !searching || (group.count ?? 0) > 0)
        .map((group) => toTree(group, searching));
      if (!groups.length) {
        treeHost.replaceChildren(hint(t("M02_PickerNoMatch")));
        return;
      }
      treeHost.replaceChildren(
        ...renderTree(groups, (node, caret, depth, onClick) => {
          const button = createTreeRow(node, caret, depth, () => {
            onClick();
            if (!node.children?.length) return;
            if (button.querySelector(".ui-tree__caret")?.textContent === "▾") opened.add(node.id);
            else opened.delete(node.id);
          });
          if (node.run) {
            leafButtons.set(node.id, button);
            if (chosen && node.id === rowId(chosen)) button.classList.add("is-active");
          }
          return button;
        }),
      );
    };

    const load = async (pickKey: string | null): Promise<void> => {
      treeHost.replaceChildren(hint(t("M02_PickerLoading")));
      try {
        rows = await loadRows();
      } catch (error) {
        treeHost.replaceChildren(
          hint(t("M02_PickerLoadFailed").replace("{value}", message(error))),
        );
        return;
      }
      const start = pickKey
        ? rows.find((row) => layerOf(row) === "personal" && row.key === pickKey)
        : rows.find((row) => isCurrent(opts.current, row));
      if (start) {
        for (const id of pathIds(start, labels())) opened.add(id);
        chosen = start;
      } else {
        opened.add("system"); // 지정된 게 없으면 첫 그룹만 펼침
      }
      paintTree();
      paintDetail();
      treeHost.querySelector(".is-active")?.scrollIntoView({ block: "nearest" });
    };

    search.input.addEventListener("input", paintTree);
    applyButton.addEventListener(
      "click",
      () => chosen && finish({ action: "apply", item: toSummary(chosen) }),
    );
    clearButton.addEventListener("click", () => finish({ action: "clear" }));
    manageButton.addEventListener("click", () => {
      finish({ action: "cancel" });
      location.hash = MANAGE_HASH;
    });
    copyButton.addEventListener("click", async () => {
      if (!chosen) return;
      copyButton.disabled = true;
      try {
        const key = await copyToPersonal(chosen);
        showToast(t("M02_PickerCopied"), "success");
        await load(key);
      } catch (error) {
        showToast(t("M02_PickerCopyFailed").replace("{value}", message(error)), "error");
      } finally {
        copyButton.disabled = false;
      }
    });

    /** 프로젝트에서 새 항목 — 개인 층에도 만들고 돌려받은 `summary_item` 을 폼에 지정 */
    async function createNew(path: string[]): Promise<void> {
      if (!opts.projectId || !opts.structureId) return;
      const where = [labels().layers.personal, ...path].join(" › ");
      const got = await askFields({
        title: NEW_TEXT.title,
        note: fill(NEW_TEXT.note, where),
        fields: [
          { key: "name", label: NEW_TEXT.name, required: true },
          { key: "unit", label: NEW_TEXT.unit, placeholder: "m · ㎥ · 개소", required: true },
        ],
        okLabel: NEW_TEXT.ok,
        cancelLabel: NEW_TEXT.cancel,
        closeLabel: t("M02_Close"),
        emptyText: NEW_TEXT.empty,
      });
      if (!got) return;
      try {
        const made: CreatedItem = await projectItems(opts.projectId).newItem(
          opts.structureId,
          path,
          got.name,
          got.unit,
        );
        showToast(NEW_TEXT.made, "success");
        finish({ action: "apply", item: made.summary_item as SummaryItem });
      } catch (error) {
        showToast(fill(NEW_TEXT.failed, message(error)), "error"); // 회사 없음 409 = 「회사부터 등록」 그대로
      }
    }

    const actions = el("div", {
      className: "ui-item-picker__actions",
      children: [
        ...(opts.projectId
          ? [el("span", { className: "ui-item-picker__saveline", text: NEW_TEXT.saveLine })]
          : []),
        copyButton,
        manageButton,
        clearButton,
        applyButton,
      ],
    });

    /** 카드 [수정] — 모달 안에서 편집 화면으로 바뀜(나무 · 카드 · 단추는 숨김) */
    function openEdit(request: EditRequest): void {
      const view = createEditView(request, closeEdit);
      editView = view;
      editHost.replaceChildren(view.root);
      cols.hidden = true;
      actions.hidden = true;
      editHost.hidden = false;
      view.start();
    }
    /** [뒤로] — 선택지로 돌아와 고른 항목을 다시 읽음(고친 값이 카드에 보임) */
    function closeEdit(saved: boolean): void {
      editView?.destroy();
      editView = null;
      editHost.hidden = true;
      cols.hidden = false;
      actions.hidden = false;
      if (saved) detailView.markEdited();
      detailView.reload();
    }

    close = openModal({
      title: t("M02_PickerTitle"),
      closeLabel: t("M02_Close"),
      dialogClass: "ui-item-picker",
      // 닫기 단추 · Esc · 바깥 누르기 = 취소 — 편집 중 저장 안 한 고침이 있으면 물음
      beforeClose: async () => {
        if (editView && !(await editView.leave())) return false;
        editView?.destroy();
        resolve({ action: "cancel" });
        return true;
      },
      mount: (body) => {
        body.append(cols, editHost, actions);
        paintDetail();
        void load(null);
      },
    }).close;
  });
}